Raman spectroscopy and microspectrophotometry of reactive dyes on cotton fibres: analysis and detection limits.

A collaborative study on Raman spectroscopy and microspectrophotometry (MSP) was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on different dyed cotton fabrics. The detection limits of the two methods were tested on two cotton sets with a dye concentration ranging from 0.5 to 0.005% (w/w). This survey shows that it is possible to detect the presence of dye in fibres with concentrations below that detectable by the traditional methods of light microscopy and microspectrophotometry (MSP). The MSP detection limit for the dyes used in this study was found to be a concentration of 0.5% (w/w). At this concentration, the fibres appear colourless with light microscopy. Raman spectroscopy clearly shows a higher potential to detect concentrations of dyes as low as 0.05% for the yellow dye RY145 and 0.005% for the blue dye RB221. This detection limit was found to depend both on the chemical composition of the dye itself and on the analytical conditions, particularly the laser wavelength. Furthermore, analysis of binary mixtures of dyes showed that while the minor dye was detected at 1.5% (w/w) (30% of the total dye concentration) using microspectrophotometry, it was detected at a level as low as 0.05% (w/w) (10% of the total dye concentration) using Raman spectroscopy. This work also highlights the importance of a flexible Raman instrument equipped with several lasers at different wavelengths for the analysis of dyed fibres. The operator and the set up of the analytical conditions are also of prime importance in order to obtain high quality spectra. Changing the laser wavelength is important to detect different dyes in a mixture.

Machine washing or brushing of clothing and its influence on shooting distance estimation.

Experiments were conducted to assess the effect of machine washing or brushing of clothing items on Gunshot Residue (GSR) patterns (gunpowder residues, lead, and copper, deposits) around bullet entrance holes. Results show that those treatments decrease considerably the amount and density of GSR. However, for close shooting distances not all of the GSR deposits are removed. Remaining patterns may be visualized by specific color reactions and used for shooting distance estimation.

Management of a patient with a complete rupture of a main bronchus in a community hospital.

We describe the successful use of a portable extracorporeal membrane oxygenation machine for a patient with complete rupture of the left main bronchus after a road crash. The machine was used before and during left main bronchus reanastomosis at a community hospital 30 km from Melbourne, and then during acute interhospital transfer.

The prognostic significance of intraventricular haemorrhage.

It is a generally held view that intraventricular haemorrhage carries a poor prognosis in cases of intracranial haemorrhage. We tested this view by retrospective analysis of the records of 258 patients who had intracranial blood on CT scans seen over a seven-year period. The mortality and morbidity for intraventricular and non-intraventricular haemorrhage were compared for the three major causes of intracranial bleeding, viz. aneurysm, trauma, and spontaneous intracerebral haemorrhage. No significant difference was found between the two groups for each aetiological category. It was concluded that the CT scan finding of intraventricular blood has no prognostic significance.